Which of the following statement is correct?

Group of answer choices

Point of Presence $($PoPs$)$ exist in all levels of the hierarchy, except for the bottom $($access ISP$)$ level.

Any ISP except tier$-1$ ISPs may choose to multi$-$ home $($i$.$e$.$ connect to two or more provider ISPs$).$

To reduce cost, a pair of nearby ISPs at the same level of the hierarchy can peer which is settlement free.

Internet Exchange Points $($IXP$)$ are operated by third party.

All of the above.